Biosensor calibration coding systems and methods

ABSTRACT

A test sensor ( 100 ) for determining an analyte concentration in a biological fluid comprises a strip including a fluid receiving area ( 128 ) and a port-insertion region ( 126 ). A first row of optically transparent ( 132 ) and non-transparent positions forms a calibration code pattern ( 130 ) disposed within a first area of the port-insertion region ( 126 ). A second row of optically transparent ( 142 ) and non-transparent positions forms a synchronization code pattern ( 140 ) disposed within a second area of the port-insertion region ( 126 ). The second area is different from the first area. The synchronization code pattern ( 140 ) corresponds to the calibration code pattern ( 130 ) such that the synchronization code pattern ( 140 ) provides synchronization of the serial calibration code pattern ( 130 ) during insertion of the port-insertion region ( 126 ) into the receiving port of the analyte meter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.15/123,334, filed on Sep. 2, 2016, now allowed, which is a U.S. NationalStage of International Application No. PCT/US2015/019020, filed Mar. 5,2015, which claims priority to and the benefits of U.S. PatentApplication No. 61/949,587, filed Mar. 7, 2014, the contents of each ofwhich is are hereby incorporated by reference herein in theirentireties.

FIELD OF THE INVENTION

The present invention generally relates to biosensors for determininganalyte concentration of a fluid sample, and more particularly, tosystems and methods of serial coding of biosensors to calibrateinstruments that determine an analyte concentration of a fluid sample.

BACKGROUND OF THE INVENTION

The quantitative determination of analytes in body fluids is of greatimportance in the diagnoses and maintenance of certain physiologicalconditions. For example, lactate, cholesterol, and bilirubin should bemonitored in certain individuals. In particular, determining glucose inbody fluids is important to individuals with diabetes who mustfrequently check the glucose level in their blood to regulate thecarbohydrate intake in their diets. The results of such tests can beused to determine what, if any, insulin or other medication needs to beadministered. In one type of testing system, test sensors are used totest a fluid such as a sample of blood.

A test sensor contains biosensing or reagent material that reacts withblood glucose. The testing end of the sensor is adapted to be placedinto the fluid being tested, for example, blood that has accumulated ona person's finger after the finger has been pricked. The fluid is drawninto a capillary channel that extends in the sensor from the testing endto the reagent material by capillary action so that a sufficient amountof fluid to be tested is drawn into the sensor. The fluid thenchemically reacts with the reagent material in the sensor and the systemcorrelates this to information relating an analyte (e.g., glucose) in afluid sample.

Diagnostic systems, such as blood-glucose testing systems, typicallycalculate the actual glucose value based on a measured output and theknown reactivity of the reagent-sensing element (test sensor) used toperform the test. The reactivity or lot-calibration information of thetest sensor may be given to the user in several forms including a numberor character that they enter into the instrument. One method includesusing an element that is similar to a test sensor, but which was capableof being recognized as a calibration element by the instrument. The testelement's information is read by the instrument or a memory element thatis plugged into the instrument's microprocessor board for directlyreading the test element.

There is an ongoing need for improved biosensors, especially those thatmay provide increasingly accurate and/or precise analyte concentrationmeasurements. The systems, devices, and methods of the present inventionovercome at least one of the disadvantages associated with encodingpatterns on sensor strips used in biosensors.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, a test sensor fordetermining an analyte concentration in a biological fluid comprises astrip including a fluid receiving area and a port-insertion region. Afirst row of optically transparent and non-transparent positions forms acalibration code pattern disposed within a first area of theport-insertion region. A second row of optically transparent andnon-transparent positions forms a synchronization code pattern disposedwithin a second area of the port-insertion region. The second area isdifferent from the first area. The synchronization code patterncorresponds to the calibration code pattern such that thesynchronization code pattern provides synchronization of the serialcalibration code pattern during insertion of the port-insertion regioninto the receiving port of the analyte meter.

According to another aspect of the present invention, a test sensor fordetermining an analyte concentration in a biological fluid comprises astrip including a fluid-receiving area and a port-insertion region. Oneor more electrical contacts are at least partially disposed within theport-insertion region. The electrical contacts are configured to alignand electrically connect with sensor contacts of an analyte meter uponinsertion of the port-insertion region into a receiving port of theanalyte meter. A serial calibration code pattern is disposed within afirst area of the port-insertion region. The serial calibration codepattern includes first optically transparent portions allowing lightwaves to be transmitted therethrough. A synchronization code pattern isdisposed within a second area of the port-insertion region. The secondarea is different from the first area. The synchronization code patternincludes second optically transparent portions allowing light waves tobe transmitted therethrough. The synchronization code patterncorresponds to the serial calibration code pattern such that thesynchronization code pattern provides synchronization of the serialcalibration code pattern during insertion of the port-insertion regioninto the receiving port of the analyte meter.

According to another aspect of the present invention, a biosensor systemfor determining an analyte concentration in a biological fluid comprisesa measurement device including a processing unit connected to an opticalpattern read device. The optical pattern read device includes one ormore light sources, a first light sensor, and a second light sensor. Asensor strip includes sequential data coding patterns including firstoptically transparent openings and separate correspondingsynchronization coding patterns including second optically transparentopenings. The one or more light sources are configured to transmit lightwaves through the first and second optically transparent openings. Theone or more light sources are at least partially positioned on a firstside of the first and second optically transparent openings. The firstlight sensor is positioned on an opposite side of the first opticallytransparent openings and the second light sensor is positioned on anopposite side of the second optically transparent openings. The firstlight sensor and the second light sensor are configured to receivetransmitted light waves from the one or more light sources. The lightwaves are transmitted by the one or more light sources and received bythe first light sensor and the second light sensor while the sensorstrip is being inserted into the measurement device such that lightwaves received by the second light sensor associated with thesynchronization coding patterns provide synchronization for the lightwaves received by the first light sensor associated with the sequentialdata coding patterns.

According to yet another aspect of the present invention, a method forcalibrating an analysis of an analyte in a biological fluid. The methodincludes the following acts: (a) transmitting light waves through firstoptically transparent openings in a test sensor including a first row ofsequential optically transparent and non-transparent positions formingcalibration coding patterns; (b) near simultaneous to act (a),transmitting light waves through second optically transparent openingsin the test sensor including a second row of sequential opticallytransparent and non-transparent positions forming synchronization codingpatterns that correspond to the calibration coding patterns; (c)receiving the light waves transmitted through the first opticallytransparent openings in a first light sensor; (d) receiving the lightwaves transmitted through the second optically transparent openings in asecond light sensor; (e) generating a series of calibration code signalsin response to light waves being received and not received by the firstlight sensor due to the optically transparent and non-transparentpositions passing the first light sensor during the insertion of thetest sensor into the analyte measuring device; (f) near simultaneous toact (e), generating a series of synchronization code signals in responseto light waves being received and not received by the second lightsensor due to the second row of sequential optically transparent andnon-transparent positions passing the second light sensor during theinsertion of the test sensor into the analyte measuring device, theseries of synchronization code signals corresponding to the series ofcalibration code signals; (g) calibrating at least one correlationequation in response to the series of calibration code signals; and (h)determining an analyte concentration in response to the at least onecalibrated correlation equation. The analyte concentration is determinedby reacting the analyte in an electrochemical reaction that produces anoutput signal. The analyte concentration is calculated using the atleast one calibrated correlation equation and the produced outputsignal.

Additional aspects of the invention will be apparent to those ofordinary skill in the art in view of the detailed description of variousembodiments, which is made with reference to the drawings, a briefdescription of which is provided below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a top view of a sensor strip with serial opticalcoding according to one embodiment.

FIG. 2 illustrates a side view of a portion of the sensor strip in FIG.1 along with aspects of an optical pattern read device according to oneembodiment.

FIG. 3 illustrates a top view of a sensor strip with serial opticalcoding inserted into a sensor interface and optical pattern read deviceaccording to one embodiment.

FIG. 4 illustrates a side view of the sensor strip in FIG. 3 accordingto one embodiment.

FIG. 5 illustrates a sensor strip adjacent to a sensor interface andoptical pattern read device along with code and synchronization signalsgenerated by the insertion of the sensor strip into the sensorinterface.

FIG. 6 illustrates another aspect of the code and synchronizationsignals generated by the insertion of the sensor strip into the sensorinterface.

FIGS. 7 and 8 illustrate sensor strips including optically transparentserial data coding patterns and synchronization coding patterns createdby punching apertures into the sensor strip according to certainembodiments.

FIG. 9 illustrates a sensor strip including optically transparent serialdata coding patterns and synchronization coding patterns created byplacing printed coding patterns on a transparent area of the sensorstrip according to one embodiment.

FIG. 10 is a flowchart of an exemplary method for calibrating ananalysis of an analyte in a fluid sample according to certainembodiments.

While the invention is susceptible to various modifications andalternative forms, specific embodiments are shown by way of example inthe drawings and are described in detail herein. It should beunderstood, however, that the invention is not intended to be limited tothe particular forms disclosed. Rather, the invention is to cover allmodifications, equivalents, and alternatives falling within the spiritand scope of the invention.

DETAILED DESCRIPTION

While this invention is susceptible of embodiment in many differentforms, there is shown in the drawings and will herein be described indetail preferred embodiments of the invention with the understandingthat the present disclosure is to be considered as an exemplification ofthe principles of the invention and is not intended to limit the broadaspect of the invention to the embodiments illustrated. For purposes ofthe present detailed description, the singular includes the plural andvice versa (unless specifically disclaimed); the word “or” shall be bothconjunctive and disjunctive; the word “all” means “any and all”; theword “any” means “any and all”; and the word “including” means“including without limitation.”

The present disclosure relates to improvements in sensors (e.g., sensorstrips, biosensors, test sensors) for systems for determining analyteconcentrations in fluid samples, such asbiological samples (e.g., bloodglucose samples). Sensors are used to collect analyte samples, such asfluid samples (e.g., blood sample, other biological fluid samples), andare inserted into an analyte concentration measurement device (e.g.,blood glucose meter) where signals may be applied to the sample via thesensors as part of determining an analyte concentration of the fluidsample. Sensors are typically manufactured in batches that arecalibrated at a manufacturing facility. Coding information may beapplied to a sensors that can be read by or otherwise determined by ananalyte concentration measurement device (e.g., blood glucose meter). Insome aspects, the calibration information is received by the devicefollowing the insertion of the sensor into the measurement device thatapplies the test signal to the sample that was received on the sensor.

Calibration information can be used to adjust the analysis of theanalyte concentration determination in response to one or morecalibration parameters (e.g., manufacturing variations, sensorexpiration date) that are encoded onto a sensor and read by an analyteconcentration measurement device. A desirable aspect of the presentdisclosure is the ability to improve the accuracy of an analyteconcentration measurement by allowing an increased amount of calibrationinformation to be encoded onto a sensor. The increased amount ofcalibration information can then be read by the measurement device aftera sensor is inserted into a sensor connector or sensor interface of themeasurement device where an increased number of calibration codes areread and processed to correct a stored equation associated with adetermination of an analyte concentration of a fluid sample. Thecalibration codes are specific to and present on the sensor itself andcan further include calibration parameters that take into account, forexample, manufacturing variations, sensor strip expiration information,and other aspects that can be corrected for when determining an analyteconcentration of a fluid sample.

Sensors, such as those used to test biological fluid samples (e.g.,blood) can include generally rectangular dimensions ranging anywherefrom about 0.1 to 0.5 inches (about 2.5 to 12.7 mm) wide by about 0.5 to1.5 inches (about 12 to 38 mm) long. In some aspects, a top surface areaof a flat test sensor can range anywhere from about 0.05 to 0.75 squareinches (about 30 to 483 mm²). Sensors typically include afluid-receiving area and an area with contacts for electricallyconnecting the sensor to the analyte concentration measurement device.Based on the relatively small size of sensors for biological fluidsampling, such as sensors for determining blood glucose concentrations,there is a very limited amount of space to encode a sensor withcalibration information that can be read from the sensor and used indetermining an analyte concentration.

The application of parallel code patterns can be used for small surfaceareas on certain sensor strips. However, parallel coding has only alimited number of code variations (e.g., typically about eight for asensor strip for biological fluids such as blood). Furthermore, parallelcoding requires the insertion of the entire coding pattern into a sensorport of a measurement device so that the entire pattern is read at thesame time. Serial code patterns can also be used and provide a highernumber of code variations (e.g., up to fifteen for a sensor strip forbiological fluids such as blood) than are typically available forparallel coding. However, serial coding typically requires a significantamount of space relative to the limited surface area available forcoding on a test sensor, such as a typical test sensor used forbiological fluid samples (e.g., blood glucose samples). For example, toincrease the number of code variations using serial coding (e.g., morethan fifteen), the length of a sensor strip would need to increase and alarger sensor port on a measurement device would be needed. It would bedesirable to encode a sensor strip with a large number of differentcalibration codes to allow for greater accuracy of analyte concentrationdeterminations, while limiting the area needed on a sensor strip toaccommodate the calibration coding patterns. The present disclosureprovides the ability to implement hundreds and even thousands ofcalibration codes within the very limited space of a sensor strip usingoptical methods where optically transparent coding patterns can be readwith an optical pattern reading device. By allowing a larger number ofcalibration codes, the accuracy of analyte concentration measurements isincreased as more factors can be used to correct the equation forcalculating an analyte concentration. An increase in calibration codesallows for more sensor specific corrections such as variations inmanufacturing or other sensor-specific factors (e.g., reagentcharacteristics, expiration date of sensor, batch number corrections)that, uncorrected, can cause a decrease in the accuracy of analyteconcentration determinations.

Turning now to FIGS. 1 and 2, a top view and side view of an exemplarybiosensor 100 (e.g., test sensor, sensor strip) is illustrated thatincludes calibration coding. The exemplary biosensor 100 is depicted asa generally flat, elongated strip, though other shapes are contemplated(e.g., forked end, tapered end, trapezoidal portions, combinations ofshapes). The biosensor includes a fluid-receiving area 128 and aport-insertion region 126. The fluid-receiving area 128 includes achannel 124 configured to receive fluid samples, such as sample of abiological fluid. The channel 124 may be sized such that capillaryaction pulls the fluid sample into the channel of the fluid-receivingarea 128. The received fluid sample can then be tested to determine ananalyte concentration using an instrument or meter after theport-insertion region 126 of the biosensor 100 is inserted into theinstrument or meter.

It is contemplated that the non-limiting exemplary sensors describedherein (e.g., biosensor 100) may be electrochemical test sensors. Insuch embodiments, an analyte meter may have optical, mechanical oroptical aspects so as to detect the calibration information andelectrochemical aspects to determine the analyte concentration of thefluid sample. While only a top view of the biosensor is illustrated inFIG. 1, such biosensors can include a base and a second layer (e.g., alid) that assist in forming the channel 124. The biosensor 100 may alsoinclude a plurality of electrodes (not shown) such as a counterelectrode, a working electrode, a trigger electrode, an underfilldetection electrode, or a hematocrit electrode in the fluid-receivingarea 128. The electrodes are coupled to conductive leads (not shown)that extend from the fluid-receiving area 128 to biosensor contacts 122a, 122 b in the port-insertion region 126. The electrodes may be atleast partially embedded between the base and lid and the conductiveleads may extend within the base and lid of the biosensor from theelectrodes to biosensor contacts 122 a, 122 b in the fluid-receivingregion. It is contemplated that electrochemical test sensors other thanthose illustrated may be employed.

The fluid-receiving area 128 includes at least one reagent forconverting the analyte of interest (e.g., glucose) in the fluid sample(e.g., blood) into a chemical species that is electrochemicallymeasurable, in terms of the electrical current it produces, by thecomponents of the electrode pattern. The reagent typically contains anenzyme such as, for example, glucose oxidase, which reacts with theanalyte and with an electron acceptor such as a ferricyanide salt toproduce an electrochemically measurable species that can be detected bythe electrodes. It is contemplated that other enzymes may be used toreact with glucose such as glucose dehydrogenase. If the concentrationof another analyte is to be determined, an appropriate enzyme isselected to react with the analyte.

A fluid sample (e.g., blood) may be applied to the fluid-receiving area128 at or near channel 124. The fluid sample travels through the channelwhere it then reacts with the at least one reagent. After reacting withthe reagent and in conjunction with the plurality of electrodes, thefluid sample produces electrical signals that assist in determining theanalyte concentration. The conductive leads carry the electrical signalback toward a second opposing end of the biosensor 100, such as theport-insertion region 126, where the biosensor contacts 122 a, 122 btransfer the electrical signals into the meter when the biosensor isinserted into the meter.

As discussed above, a sensor may analyze the analyte in a sample usingan electrochemical analysis. It is also contemplated that a sensor mayanalyze the analyte in a sample using an optical analysis or acombination of optical and electrochemical methods. As discussed above,during electrochemical analyses, an excitation signal is applied to thesample of the biological fluid. The excitation signal may be a potentialor current and may be constant, variable, or a combination thereof. Theexcitation signal may be applied as a single pulse or in multiplepulses, sequences, or cycles. Various electrochemical processes may beused such as amperometry, coulometry, voltammetry, gated amperometry,gated voltammetry, and the like.

Optical test sensor systems may use techniques, such as transmissionspectroscopy, diffuse reflectance, spectroscopy, or fluorescencespectroscopy, for measuring the analyte concentration. Anindicator-reagent system and an analyte in a sample of body fluid arereacted to produce a chromatic reaction, as the reaction between thereagent and analyte causes the sample to change color. The degree ofcolor change is indicative of the analyte concentration in the bodyfluid.

An optical test sensor can include auto-calibration information and asample-receiving area (e.g., fluid-receiving area). The sample-receivingarea includes an indicator-reagent system that is adapted to produce achromatic reaction after being exposed to an analyte in a fluid sample.The reagent may be dried and then mixed with the sample in thesample-receiving area. Alternatively, the reagent may be deposited withthe sample or after the sample has been received in the sample-receivingarea.

An optical analysis generally measures the amount of light absorbed orgenerated by a reaction of a chemical indicator with an analyte. Anenzyme may be included with the chemical indicator to enhance thereaction kinetics. The light from an optical system may be convertedinto an electrical signal such as current or potential by a detector.

In light-absorption optical analyses, a chemical indicator produces areaction product that absorbs light. An incident excitation beam from alight source is directed toward the sample. The incident beam may bereflected back from or transmitted through the sample to a detector orsensor. The detector collects and measures the attenuated incident beam.The amount of light attenuated by the reaction product is an indicationof the analyte concentration in the sample.

In light-generated optical analyses, the chemical indicator produces areaction product that fluoresces or emits light in response to theanalyte during the redox reaction. A detector collects and measures thegenerated light. The amount of light produced by the chemical indicatoris an indication of the analyte concentration in the sample.

A biosensor can be made from a variety of materials such as polymericmaterials. Non-limiting examples of polymeric materials that may be usedto form a base, a lid, and any spacers of a biosensor includepolycarbonate, polyethylene terephthalate (PET), polyethylenenaphthalate (PEN), polyimide, and combinations thereof. It iscontemplated that other materials may be used in forming a biosensorbase, lid, and/or spacer.

To form the biosensor, the base, the spacer, and the lid are attachedby, for example, an adhesive or heat sealing. When the base, the lid,and/or the spacer are attached, the fluid-receiving area 128 and channel124 are formed. The fluid-receiving area 128 provides a flow path forintroducing the fluid sample into the biosensor.

The exemplary biosensor 100 depicted in FIG. 1 also includes a serialcalibration code pattern 130 disposed generally along a first side 112of the biosensor 100. The serial calibration code pattern 130 includesoptically transparent portions (e.g., 132) that allow light waves to betransmitted therethough. The biosensor 100 further includes asynchronization code pattern 140 disposed generally along a second side114 of the biosensor 100. The synchronization code pattern 140 alsoincludes optically transparent portions (e.g., 142) that allow lightwaves to be transmitted therethrough with optically transparent openingsbeing generally evenly spaced along the pattern 140 with opticallynon-transparent portions in between. While the serial calibration codepattern 130 and the synchronization code pattern 140 are depicted as twoparallel strings on two opposing sides 112, 114 of the biosensor 100, itis contemplated that the strings can be offset from each other or evenlocated adjacent to each other with at least some separation or barrierbetween the respective patterns 130, 140 as long as the synchronizationcode pattern 140 corresponds to the serial calibration code pattern 130.The correspondence between these two patterns 130, 140 providessynchronization of the serial calibration code pattern 130 duringinsertion of the port-insertion region 126 into a receiving port of ananalyte meter, which will be discussed in more detail below including inthe context of FIGS. 2-6.

The benefit of combining a serial calibration code pattern with acorresponding synchronization code pattern on a sensor is that a largenumber of different calibration codes can be encoded onto the sensorwithin a limited area allowing the test sensor size to remain relativelyunchanged while still allowing the sampling of a biological fluid andinsertion of the sensor into an analyte measurement meter. For example,the non-limiting embodiment of biosensor 100 and variations thereofallows for anywhere from hundreds to thousands of calibration codeswithin the very limited space of the biosensor 100 through the use ofthe optically transparent coding patterns that can be read with anoptical pattern reader associated with the analyte measurement meter.The illustrated sixteen optically transparent synchronization openingsalong pattern 140, allow up to 65,536 (i.e., 2 to the 16^(th) powerassuming the meter is operating in binary) different calibration codescan be available for applying a correction to an analyte concentrationdetermination. If only half the synchronization openings were used, upto 256 (i.e., 2 to the 8^(th) power assuming the meter is operating inbinary) different calibration codes would be available. Similarly, ifonly a quarter of the synchronization openings were used, up to 16(i.e., 2 to the 4^(th) power assuming the meter is operating in binary)different calibration codes would be available. Thus, the number ofcalibration codes that are available is exponentially related to thenumber of synchronization openings disposed on the sensor. Whileproviding what could be nearly an unlimited number of calibration codesusing serial calibration coding methods, the addition of synchronizationcoding allows this to be done within the same amount of surface area ona sensor strip that would normally be occupied by parallel codingmethods. A significant increase in the number of available calibrationcodes increases the accuracy and precision of analyte concentrationmeasurements.

A biosensor can include at least a portion of the serial calibrationcode pattern or at least a portion of the synchronization code patternbeing formed by apertures or holes (e.g., 132, 142) in the test sensormaterial. The patterns may also be formed using optically transparentmaterials separated by non-transparent portions. For the synchronizationcode patterns, the apertures or optically transparent opening arearranged in an evenly spaced manner in serial fashion as illustrated,for example, in synchronization code pattern 140 where thesynchronization code pattern has evenly distributed openings eachseparated by evenly distributed optically non-transparent material. Theevenly spaced synchronization code patterns act as clock pulses that aresynchronized with the calibration coding pattern. The calibration codepatterns can also include apertures or optically transparent materialsarranged in a serial fashion on the sensor, but may not be evenly spacedand may include a series of larger apertures or optically transparentopenings separated by non-transparent portions to create the patternassociated with a calibration code. The patterns can be read using anoptical pattern reader. In certain aspects, the serial calibration andsynchronization code patterns each have a certain length that isdetermined by the combination of the optically non-transparent portionsand the optically transparent openings that in combination comprise thecalibration or synchronization pattern. In some aspects, depending onhow the two patterns correspond to each other for synchronizationpurposes, the synchronization code pattern on the sensor may beapproximately the same length as the serial calibration code pattern.

As illustrated in FIG. 1, the serial calibration code pattern 130 can bedisposed on the sensor parallel to the synchronization code pattern 140.In FIG. 1, the patterns 130, 140 are disposed on opposing sides 112, 114of the test sensor. The serial calibration code pattern is disposed onthe sensor parallel to and physically separated from the synchronizationcode pattern by an optically non-transparent portion of the sensor.However, it is contemplated that the code patterns 130, 140 can bedisposed at other locations on the test sensor so long at thesynchronization code pattern corresponds to the calibration codepattern.

In some aspects, it is contemplated that a test sensor can include aport-insertion region having a first side and an opposing second side.The serial calibration code pattern can be oriented parallel to andalong the first side (e.g., an edge of the sensor), and thesynchronization code pattern can be oriented parallel to and along thesecond side (e.g., another edge of the sensor). In certain aspects, theserial calibration code pattern and the synchronization code patterneach include apertures disposed in the strip along the first side andthe second side. Each of the apertures of the code patterns may begenerally rectangular with all the sides of the apertures (or in someinstances less than all the sides—e.g., only three sides of theapertures) being defined by the test sensor.

The surface area of the test sensor that is occupied by calibration andsynchronization code patterns, while still providing a large number ofcalibration codes, can be minimized by applying the features describedby the present disclosure. For a configuration that provides for up toapproximately 65,536 calibration codes, the serial calibration codepattern in some aspects occupies less than 0.04 square inches of a topsurface area of the sensor. In some aspects, the serial calibration codepattern occupies less than 0.02 square inches of a top surface area ofthe sensor. In some aspects, the synchronization code pattern occupiesless than 0.04 square inches of a top surface area of the sensor. Insome aspects, the synchronization code pattern occupies less than 0.02square inches of a top surface area of the sensor. In some aspects, theserial calibration code pattern and the synchronization code patterntogether occupy less than 0.06 square inches of a top surface area ofthe sensor. In certain aspects, the serial calibration code pattern andthe synchronization code pattern together occupy less than 0.03 squareinches of a top surface area of the sensor.

Referring now to FIG. 2, an exemplary side view of the biosensor 100 isdepicted along with an artificial light source 160 and light sensor 170that may be part of an optical pattern reader used to obtain dataencoded onto the biosensor 100. In some aspects, it is contemplated thatthe artificial light source 160 may be a light-emitting diode (LED) oranother light source that is known for optical readers in the field ofanalyte concentration testing. It is contemplated that the light sensor170 can be a photosensor, an array of light detectors, or anotherlight-sensitive sensor that is known for optical readers in the field ofanalyte concentration testing.

The test sensor can include a plurality of apertures (e.g., 132, 142)that form the coding patterns. The apertures (e.g., 142) are depicted asclear (unhatched) areas in the side view of FIG. 2. The synchronizationcode pattern 140 illustrate in FIG. 1 and the cross-sectional viewillustrated in FIG. 2 shows a plurality of synchronization codeapertures where each of the apertures are evenly spaced and correspondto the calibration code pattern (e.g., 130) illustrated in FIG. 1. Thecorrespondence between the two patterns is illustrated and described inmore detail with respect to FIG. 6. One non-limiting example of acalibration code pattern 130 is shown in FIG. 1 with less than all ofthe potential apertures that could be coded onto the sensor. Theselection of which apertures to form for the calibration code patterndetermines the calibration code conveyed to the meter or instrument,which is associated with sensor-specific calibration information.

The apertures 132, 142 may be formed by cutting or punching of a testsensor. The cutting or punching may be performed by lasers, mechanicalpunching, die cutting or by using water jets. The shape of the apertures132, 142 is shown as being a thin generally rectangular slit. Othershapes are contemplated by the present disclosure includes shapesdifferent from the generally rectangular shapes, such as those depictedin FIGS. 1-9.

It is contemplated that a plurality of optically transparent openings(e.g., 132, 142), such as an aperture, are combined to form therespective coding patterns. The optically transparent openings caninclude an aperture extending entirely through a sensor (e.g., 100), atransparent opening formed from an optically transparent materialextending through the sensor, or through a combination aperturespartially extending through a sensor and a remaining portion ofoptically transparent material. An optically transparent opening allowslight to be transmitted through and detected on the opposing side of thesensor. Non-limiting examples of optically clear or translucent materialthat may be used include “white” or clear polyethylene terephthalate(PET), “white” or clear polycarbonate, or “white” or clearglycol-modified PET (PETG). Alternatively, an optically clear substratemay be covered with an opaque coating that is then selectively removedto form optically transparent openings. Examples of such opaque coatingsare metals, such as aluminum, gold or copper formed by vacuumdeposition, sputtering or plating, and carbon, which may be coated orprinted.

The light source 160 illustrated in FIG. 2 can be part of an opticalpattern read device that includes one or more of the light sources and aplurality of light sensors (e.g., 170). The artificial light source 160can include a light-emitting diode (or other type of light) 162 that maybe covered by a light mask 164 shaped to direct light generated by theLED through a narrow mask opening 168, and into the opticallytransparent openings defining the codes, such that a light beam 180 fromthe light source is received by the light sensor 170. The light sensor170 can include a photosensor 172 or other light sensing element thatmay be covered by a sensor mask 174 that may further include a narrowlight receiving opening 178. The use of masks 168, 178 can be beneficialfor directing the light beam 180 directly into an optically transparentcode opening and also for minimizing or preventing the receipt of anyerrant light from another light source that might give a false positivedetection by the light sensor 170. The masks can also be configured, atleast for the light source, so that the emitted light beam is narrowerthan the smallest dimension of the optically transparent openings (e.g.,apertures). While FIG. 2 illustrates a cross-section through asynchronization code pattern, the light source and light sensor featuresand the aspects of transmitting light through an optically transparentopening (e.g., 132, 142) is generally the same for both thesynchronization and calibration code patterns.

The artificial light source 160 and light sensor 170 may be part of abiosensor system for determining an analyte concentration in abiological fluid. The biosensor system may include a measurement deviceincluding a processing unit connected to an optical pattern read device.The optical pattern read device can include one or more light sourcesand a plurality of light sensors. A sensor strip, such as sensor 100illustrated in FIGS. 1 and 2, includes sequential data coding patternsincluding first optically transparent openings (e.g., 132, 142) andseparate corresponding synchronization coding patterns including secondoptically transparent openings. The one or more light sources (e.g.,160) can be configured to transmit light waves through the first andsecond optically transparent openings (e.g., 142). The one or more lightsources are at least partially positioned on a first side of the firstand second optically transparent openings. One of the plurality of lightsensors (e.g., 170) is positioned on an opposite side of the firstoptically transparent openings (e.g., 132) and another of the pluralityof light sensors is positioned on an opposite side of the secondoptically transparent openings (e.g., 142). The light sensors (e.g.,170) are configured to receive transmitted light waves from the one ormore light sources. The light sensors generate a sequence of pulses inresponse to the light waves or light beams being transmitted through theoptically transparent openings associated with the sequential datacoding patterns and the synchronization coding patterns.

In some aspects, the one or more artificial light sources may be just asingle light source (e.g., 160). A plurality of light guides (not shown)can be employed to receive light from an LED light (e.g., 162) andredirect the light beam from the light to the optically transparentopenings. One light guide can direct the light beam to the calibrationcode pattern and another light guide can direct the split light beam tothe synchronization code pattern. The light beams are directed by totalinternal reflection within the plurality of light guides. It is alsocontemplated that the light beams may further be redirected byreflecting surfaces present in the light guide(s). The plurality oflight guides can further be configured to emit light beams narrower thanthe smallest dimension of the optically transparent openings.

In some aspects, the one or more light sources may include two lightsources (e.g., LEDs). One light may be positioned to transmit lightwaves through first optically transparent openings and into the firstlight sensor that may be associated with the serial calibration codepatterns. The other light may be positioned to transmit a light beamthrough the second optically transparent openings and into the secondlight sensor associated with the serial synchronization code patterns.

Turning now to FIGS. 3 and 4, a top view and a side view are illustratedof a sensor strip 300 with serial optical coding that is inserted into asensor interface 390 including an optical pattern read device 380. Thesensor 300 includes a port-insertion region 326 and a fluid-receivingarea 328. The port-insertion region 326 of the sensor 300 can beinserted into the sensor interface 390 as illustrated in FIGS. 3 and 4.As the sensor 300 is inserted into the sensor interface 390, sensordetection contacts 394 a, 394 b will complete a circuit as contact 394 bis pushed up and touches contact 394 a to complete the detectioncircuit. A first end 396 of a sensor detection contact 394 b can bepositioned at the portion of the sensor interface where the sensor isfirst inserted and before the sensor is placed below the optical patternreader. The completion of the circuit between contacts 394 a and 394 bcauses a signal to be received in a controller or other processing unitthat initiates instructions for the optical pattern read device 380 tobegin transmitting light from light source(s) 360 to light sensor(s) 370as the sensor 300 is inserted into the sensor interface. Thetransmitting and receiving of light is configured to occur as thecalibration code patterns and corresponding synchronization codepatterns pass through the light beam created by the light source-lightsensor arrangement.

As the sensor 300 is inserted into the sensor interface, the codepattern is read by the optical pattern read device so that a calibrationcode can be determined for use in an equation for determining an analyteconcentration for a fluid sample received in the fluid-receiving area.The sensor 300 includes contacts 312 a, 312 b that complete a circuitwith sensor interface contacts 392 a, 392 b, which are used toelectrochemically determine a value associated with an analyteconcentration for the received fluid sample in the fluid-receiving area328. The sensor interface may be associated with or be a part of ameasurement device in a biosensor system for determining an analyteconcentration in a biological fluid. For example, the sensor interfacemay be a part of a blood glucose meter or another analyte meter andcomprise all or a portion of a sensor receiving area of such meters.

In some aspects, it is contemplated that a sensor strip detection systemdetects a sensor strip being inserted into a port of a measurementdevice, such as an analyte meter. The sensor strip is detected by thedetection system immediately prior to commencing the optical reading ofthe sequential or serial data coding patterns and the synchronizationcoding patterns.

An optical pattern read device (e.g., 380) including light sources(e.g., 160, 360) and light sensors (e.g., 170, 370) are configured tomeasure optical transmissions through an array of fine opticallytransparent openings for the serial calibration and synchronizationcodes disposed in a biosensor. In some aspects, and as illustrated forexample in FIGS. 2 and 4, the light sensor (or light receiver) isdisposed on the opposite side of a sensor from where the light beamgenerated by the artificial light source first enters the opticallytransparent opening in the sensor. It is contemplated that similararrangements of the artificial light source and light sensor areapplicable for reading both the serial synchronization code patterns andthe serial calibration code patterns on a sensor. As illustrated by thenon-limiting embodiment of FIGS. 3 and 4, as the sensor is moving orinserted into a port or sensor interface, the light sensor (e.g., 370)generates a sequence of pulses in response to the receipt or lackthereof of artificial light beams transmitted from the light source. Thereceipt of an artificial light beam by the sensor occurs in when anoptically transparent opening (e.g., aperture associated with coding) ispresent between the light source and receiver. The lack of receipt ofartificial light occurs when an optically non-transparent portion isdisposed on the sensor, for example between two optically transparentopenings, and blocks a light beam from being received by the lightsensor.

It is contemplated that the optical pattern read device may include amicrocontroller (or be associated with a microcontroller or anotherprocessing unit) that processes the data pulses to determine thecalibration code for the test sensor. The received calibration datapulses correspond with the synchronization pulses to allow for a largenumber of calibration codes to be available in a limited space. Forexample, while a sensor strip is being inserted into the measurementdevice, light waves or light beams may be transmitted by both the firstand second light sources and received by a first light sensor associatedwith serial or sequential calibration code patterns and a second lightsensor associated with serial or sequential synchronization codepatterns. The light waves or light beam received by the second lightsensor provides synchronization for the light waves received by thefirst light sensor.

Turning now to FIGS. 5 and 6, a non-limiting top view of an exemplarysensor strip 500 is depicted adjacent to a sensor interface 590 havingoptical read features such as a calibration light source 580 and asynchronization light source 560, each having respective sensors (notshown) opposite the light source with a small gap therebetween to allowfor passage of the sensor, and more specifically, passage of therespective exemplary serial calibration code pattern 530 and exemplaryserial synchronization code pattern 540. The synchronization codepattern 540 includes a first optically transparent opening 542 afollowed by a series of additional evenly spaced optically transparentopenings and ending with a last optically transparent opening 542 b.Each opening in the synchronization code pattern includes a front side(e.g., 544 a) and an end side (e.g., 544 b) corresponding to thebeginning and the end of the optically transparent opening identifiableby an optical pattern reader (e.g., including one or more light sourceand light sensor combinations).

FIG. 5 also illustrates a non-limiting example of the type of “SerialData” signals generated by the light sensor associated with the serialcalibration code pattern 530 and the corresponding “Synchronization”signals generated by the light sensor associated with the serialsynchronization code pattern 540. A first pulse signal 552 a of thesynchronization code pattern corresponds to exemplary first opening 542a and a last pulse signal 552 b corresponds to exemplary last opening542 b. An initial spike (e.g., 554 a) of a pulse corresponds to theoptical pattern reader identifying the front side (e.g., 544 a) of acode pattern opening and the end spike (e.g., 554 b) corresponds to theoptical reader identifying the end side (544 b) of the same codepattern. More details of non-limiting exemplary aspects regarding thesynchronization and calibrations code patterns and the correspondencebetween the two is depicted in FIG. 6 along with the determination ofthe binary data generated from the code patterns.

As illustrated in FIGS. 5 and 6, the sequential or serial data codingpatterns (e.g., 530) and the synchronization coding patterns (e.g., 540)cause a series of corresponding positive (e.g., “1”) and negative (e.g.,“0”) code signals to be generated by the optical read head device. Thesecode signals are received by the processing unit and processed in abinary form (e.g., “0” and “1”). The code signals are received while thesensor strip is inserted into the measurement device. The measurementdevice (e.g., an analyte meter) and sensor strip are configured toimplement an analyte analysis having at least one correlation equationassociated with a calibration code determined from the sequential datacoding patterns. A processing unit is configured to calibrate the atleast one correlation equation in response to the generated code signalsreceived from the optical pattern read device. The processing unit isfurther configured to determine an analyte concentration responsive tothe at least one calibrated correlation equation.

In it contemplated that the synchronization code pattern can includeanywhere from between about eight to about sixteen or more sequentialand evenly spaced optically transparent openings disposed on a testsensor. Each of the evenly spaced synchronization code openings (e.g.,540) corresponds to one of a series of sequential optically transparentopenings and non-transparent positions that comprise the calibrationcode pattern (e.g., 530) on the same test sensor.

Referring now to FIG. 6, a portion of a test sensor that includes theport-insertion region is depicted, similar to the sensor illustrated inFIG. 5 (including similar serial data and synchronization codings). Thisnon-limiting example of a coded test sensor includes a series ofoptically transparent openings 632 a, 632 c, 632 e, 632 g, 632 i thatare respectively separated by optically non-transparent portions 632 b,632 d, 632 f, 632 h that are disposed on the test sensor. The testsensor can be inserted into a port or opening of an analyte meter indirection 670. As the test sensor is inserted into the port, signals aregenerated by a light sensor of an optical pattern read device. Thegenerated signal is depicted by the “Serial Data” illustrated in FIG. 6.As calibration code opening 632 a passes between a light source andlight sensor, as described, for example in FIG. 2, a positive signal isgenerated by the light sensor in response to receiving the light beamtransmitted from the light source. The positive signal may beinterpreted in binary form as a “1” by a processor (e.g.,microcontroller) associated with (e.g., connected to) the light sensoror the optical pattern read device. Next, an optically non-transparentportion 632 b passes between the light source and light sensorgenerating a negative signal by the light sensor as a light beam is notreceived from the light source. The negative signal may be interpretedin binary form as a “0” by the processor.

Near simultaneous to the generation of the serial data from the serialcalibration code pattern, a corresponding synchronization code patternis being read and a light sensor generates signals (e.g.,“Synchronization”) that act as a clocking system for respectivepositions of the corresponding optically transparent openings andoptically non-transparent portions of the calibration coding pattern.For example, optically transparent synchronization code opening 642 a is“clocked” to correspond to optically transparent calibration codeopening 632 a. Optically non-transparent synchronization portion 642 bis “clocked” to correspond to optically non-transparent calibrationportion 632 b. In some aspects, the synchronization code patterncomprises a series of similarly sized optically transparent openingsthat are evenly spaced in series with a similarly sized gap of opticallynon-transparent material the optically transparent openings.

Referring again to the calibration code openings for test sensor in FIG.6, after the optically non-transparent portion 632 b causes a generationof a negative signal, a series of calibration positions that formoptically transparent opening 632 c causes a series of positive signalsto be generated by the optical pattern read device in correspondencewith clocking or synchronization signals generated by thesynchronization light sensor for the optically transparentsynchronization code openings. In the non-limiting example of opening632 c, the generated positive signals are interpreted by the processorin a binary form of “1-1-1-1”. This is followed by a series ofcalibration positions that form another optically non-transparentportion 632 d that causes a series of negative signals to be generatedby the optical pattern read device in correspondence with clocking orsynchronization signals generated by the synchronization light sensorfor the synchronization code opening that correspond with the series ofcalibration positions associated with portion 632 d. The generatednegative signals are interpreted by the processor in a binary form of“0-0-0”. Similar generation of signals and subsequent processorinterpretations occur for openings 632 e, 632 g 632 i and portions 632f, 632 h in correspondence with their respective synchronization codeopenings.

The number of synchronization code openings determines the number ofpossible calibration codes for a test sensor. For example, FIG. 6includes sixteen evenly spaced synchronization code openings (e.g., 642a) that allow for a pattern including sixteen calibration code positionsthat can be either a “1” or a “0” depending on if a positive a negativesignal is generated for a particular calibration position. This meansthat the maximum number of possible calibration codes for thisnon-limiting embodiment is 65,536 codes (i.e., 2{circumflex over( )}16). More or fewer calibration codes are possible by adding orremoving the number of synchronization code openings, and thus, addingor removing the number of calibration code positions. The number ofpossible calibration codes increases and decrease exponentially (by afactor of two in the exemplary binary aspect illustrated for the presentdisclosure) for each added or removed synchronization opening.Furthermore, while FIGS. 5 and 6 depict a generated calibration signalcorresponding to a binary calibration code of “1011110001010001”, thisis just one of 65536 calibration codes (e.g., ranging from0000000000000000 to 1111111111111111) that can be generated by changingthe serial pattern of optically transparent calibration openings andoptically non-transparent calibration portions comprising thecalibration coding pattern on a test sensor.

Turning now to FIGS. 7 and 8, two non-limiting exemplary aspects of testsensors 700, 800 are depicted. Test sensors 700, 800 include opticallytransparent serial data coding patterns created by punching apertures(e.g., 732, 832) into the sensor strips. Test sensor 700, 800 alsoincludes optically transparent synchronization coding patterns alsocreated by punching apertures (e.g., 742, 842) into the sensor strip.The apertures (e.g., 732, 832) for the serial data coding can be ofvarying sizes that depend on the calibration code for a sensor andwhether a given position along the calibration coding is intended togenerate a positive or negative signal. Thus, if a given aperture iscoded to provide a series of positive signals (e.g., “1-1-1”), theaperture will be wider than an aperture that is coded to only provide asingle positive signal (e.g., “1”) preceding and followed by one or moreportions intended to generate a negative signal (e.g., “0”). Theapertures (e.g., 742, 842) for the synchronization coding patterns aregenerally the same size and are evenly spaced in a serial fashion. Theapertures 732, 742 in sensor 700 are generally rectangular and aredisposed entirely within the sensor 700 such that sensor material formsa perimeter around each aperture. The apertures 832, 842 in sensor 800are generally square or rectangular and are disposed along the perimeterof the sensor 800 such that sensor material only forms a partialperimeter around each aperture. While generally rectangular shapes aredepicted for the apertures 732, 742, 832, 842, it is contemplated thatother shapes can be used as would be understood in the field of opticalpattern readers.

Turning now to FIG. 9, a sensor strip 900 is depicted includingoptically transparent serial data coding patterns and synchronizationcoding patterns created by placing printed coding patterns 930, 940 on atransparent area 934, 944 of the sensor strip. Similar to other sensorsdescribed above, the sensor strip 900 may include a port-insertionregion 926 and a fluid-receiving area 928. The port-insertion region 926can include two sections 934, 944 of optically transparent material. Afirst section 934 of optically transparent material can have acalibration overlay 930 adhered to or printed onto the opticaltransparent layer 934 to form a pattern for the serial calibrationcoding for the sensor strip 900. The calibration overlay 930 can have aplurality of data openings (e.g., 932) printed, punched, or otherwisecut into the overlay. Similarly, a second section 944 of opticallytransparent material can have a synchronization overlay 940 adhered toor printed onto the optical transparent layer 944 to form a pattern forthe serial synchronization coding for the sensor strip 900. Thesynchronization overlay 940 can have a plurality of synchronizationopenings (e.g., 942) printed, punched, or otherwise cut into theoverlay.

Turning now to FIG. 10, a flowchart for an exemplary method forcalibrating an analysis of an analyte in a biological fluid isillustrated. The actions identified in the flowchart and described belowcorrespond to instructions that may be stored in a memory and executedby one or more processing units within or connected to a fluid analytemeter, such as a blood glucose meter or other types of fluid analytemeters including portable or stationary units. First, at step 1010, themethod includes the act of transmitting light waves through firstoptically transparent openings in a test sensor that includes a firstrow of sequential optically transparent and non-transparent positionsforming calibration coding patterns. Next, at step 1012, nearlysimultaneous to the act in step 1010, the act of transmitting lightwaves through second optically transparent openings in the test sensoris implemented. The transparent openings include a second row ofsequential optically transparent and non-transparent positions on thetest sensor that form synchronization coding patterns that correspond tothe calibration coding patterns. Then, at step 1014, the light wavestransmitted through the first optically transparent openings arereceived by a first light sensor, and at step 1016, light wavestransmitted through the second optically transparent openings arereceived by a second light sensor. Next, at step 1018, the act ofgenerating a series of calibration code signals is implemented inresponse to light waves being received and not received by the firstlight sensor. The light waves are received and not received in responseto the optically transparent and non-transparent positions passing thefirst light sensor during the insertion of the test sensor into theanalyte measuring device. Then, at step 1020, nearly simultaneous to theact in step 1018, the act of generating a series of synchronization codesignals is implemented in response to light waves being received and notreceived by the second light sensor. The light waves are received andnot received in response to the second row of sequential opticallytransparent and non-transparent positions passing the second lightsensor during the insertion of the test sensor into the analytemeasuring device. The series of synchronization code signals correspondto the series of calibration code signals. Next, at step 1022, the actof calibrating at least one correlation equation is implemented by oneor more processing units in response to the generated series ofcalibration code signals. Finally, at step 1024, the act of determiningan analyte concentration is implemented by at least one of the one ormore processing units based on the at least one calibrated correlationequation. The analyte concentration determination further includesreacting the analyte in an electrochemical reaction that produces anoutput signal. The analyte concentration is then calculated using the atleast one calibrated correlation equation and the produced outputsignal.

In some aspects, it is contemplated that a method for calibrating ananalysis of an analyte in a biological fluid can further includedetecting the insertion of the test sensor into an insertion port of ananalyte meter. The detecting can occur immediately prior to transmittingof light waves or a light beam through optically transparent openingsand non-transparent positions forming the calibration coding patternsand the synchronization coding patterns. It is further contemplated thatcalibration coding patterns have a length where the synchronizationcoding patterns are about the same length as the calibration codingpatterns. In some aspects, the second row of sequential opticallytransparent and non-transparent positions are evenly spaced. Thecalibration coding patterns may be disposed on the test sensor parallelto and physically separated from the synchronization coding patterns byan optically non-transparent portion of the strip.

While the invention has been described with reference to details of theillustrated embodiments, these details are not intended to limit thescope of the invention as defined in the appended claims. For example,although the illustrated embodiments are generally directed to asynchronization code pattern that includes sixteen positions oroptically transparent openings, coding patterns with more or feweroptically transparent openings, along with different arrangements, arecontemplated to provide a clocking mechanism for the calibration codepatterns. Furthermore, different types of optically transparent openingsare contemplated including hybrids of both transparent material andpartial apertures in the test sensor material. In addition, it should benoted that the cross-section and other geometrical aspects of the sensorinterface, light sources, light sensors, and sensors used herein may beother shapes such as circular, square, hexagonal, octagonal, otherpolygonal shapes, or oval. The non-electrical components of theillustrated embodiments are typically made of a polymeric material.Non-limiting examples of polymeric materials that may be used in formingdevices and strips include polycarbonate, ABS, nylon, polypropylene, orcombinations thereof. It is contemplated that the fluid analyte systemscan also be made using non-polymeric materials. The disclosedembodiments and obvious variations thereof are contemplated as fallingwithin the spirit and scope of the claimed invention.

Alternative Aspects

According to an alternative aspect A, a test sensor for determining ananalyte concentration in a biological fluid includes a strip including afluid-receiving area and a port-insertion region; a first row ofoptically transparent and non-transparent positions forming acalibration code pattern disposed within a first area of theport-insertion region; and a second row of optically transparent andnon-transparent positions forming a synchronization code patterndisposed within a second area of the port-insertion region, the secondarea being different from the first area, wherein the synchronizationcode pattern corresponds to the calibration code pattern such that thesynchronization code pattern provides synchronization of the calibrationcode pattern during insertion of the port-insertion region into areceiving port of an analyte meter.

According to an alternative aspect B, the test sensor of the precedingaspect further includes that the test sensor is an electrochemical testsensor, the strip further including one or more electrical contacts atleast partially disposed within the port-insertion region, theelectrical contacts configured to align and electrically connect withsensor contacts of the analyte meter upon insertion of theport-insertion region into the receiving port.

According to an alternative aspect C, the test sensor of any one ofpreceding aspects A or B further includes that the calibration codepattern and the synchronization code pattern include at least oneaperture in the strip, the at least one aperture defining one or more ofthe optically transparent positions.

According to an alternative aspect D, the test sensor of any one ofpreceding aspects A to C further includes that the calibration codepattern has a length, the synchronization code pattern having the samelength as the calibration code pattern.

According to an alternative aspect E, the test sensor of any one ofpreceding aspects A to D further includes that the positions forming thecalibration code pattern are linearly disposed on the strip parallel tothe synchronization code pattern.

According to an alternative aspect F, the test sensor of any one ofpreceding aspects A to E further includes that the calibration codepattern is disposed on the strip parallel to and physically separatedfrom the synchronization code pattern by an optically non-transparentportion of the strip.

According to an alternative aspect G, the test sensor of any one ofpreceding aspects A to F further includes that the port-insertion regionincludes a first edge and an opposing second edge, the calibration codepattern being oriented parallel to and along the first edge, thesynchronization code pattern being oriented parallel to and along thesecond edge.

According to an alternative aspect H, the test sensor of any one ofpreceding aspects A to G further includes that the calibration codepattern and the synchronization code pattern each include aperturesdisposed in the strip along the first edge and the second edge, each ofthe apertures of the code patterns being generally rectangular with onlythree sides of the apertures being defined by the strip.

According to an alternative aspect I, the test sensor of any one ofpreceding aspects A to H further includes that the test sensor includesa reagent, the reagent including glucose oxidase and/or glucosedehydrogenase.

According to an alternative aspect J, the test sensor of any one ofpreceding aspects A to I further includes that the calibration codepattern includes between about eight and about sixteen opticallytransparent first openings and the synchronization code pattern includesbetween about eight and about sixteen optically transparent secondopenings.

According to an alternative aspect K, the test sensor of any one ofpreceding aspects A to J further includes that the calibration codepattern occupies less than 0.04 square inches of a top surface of thestrip.

According to an alternative aspect L, the test sensor of any one ofpreceding aspects A to J further includes that the calibration codepattern occupies less than 0.02 square inches of a top surface of thestrip.

According to an alternative aspect M, the test sensor of any one ofpreceding aspects A to L further includes that the synchronization codepattern occupies less than 0.04 square inches of a top surface of thestrip.

According to an alternative aspect N, the test sensor of any one ofpreceding aspects A to L further includes that the synchronization codepattern occupies less than 0.02 square inches of a top surface of thestrip.

According to an alternative aspect O, the test sensor of any one ofpreceding aspects A to N further includes that the calibration codepattern and the synchronization code pattern together occupy less than0.06 square inches of a top surface of the strip.

According to an alternative aspect P, the test sensor of any one ofpreceding aspects A to N further includes that the calibration codepattern and the synchronization code pattern together occupy less than0.03 square inches of a top surface of the strip.

According to an alternative aspect Q, the test sensor of any one ofpreceding aspects A to P further includes that the test sensor is anoptical test sensor.

According to an alternative aspect R, a test sensor for determining ananalyte concentration in a biological fluid includes a strip including afluid-receiving area and a port-insertion region, one or more electricalcontacts at least partially disposed within the port-insertion region,the electrical contacts configured to align and electrically connectwith sensor contacts of an analyte meter upon insertion of theport-insertion region into a receiving port of the analyte meter; aserial calibration code pattern disposed within a first area of theport-insertion region, the serial calibration code pattern includingfirst optically transparent portions allowing light waves to betransmitted therethrough; and a synchronization code pattern disposedwithin a second area of the port-insertion region, the second area beingdifferent from the first area, the synchronization code patternincluding second optically transparent portions allowing light waves tobe transmitted therethrough, wherein the synchronization code patterncorresponds to the serial calibration code pattern such that thesynchronization code pattern provides synchronization of the serialcalibration code pattern during insertion of the port-insertion regioninto the receiving port of the analyte meter.

According to an alternative aspect S, the test sensor of the precedingaspect further includes that the serial calibration code pattern isdisposed on the strip parallel to the synchronization code pattern.

According to an alternative aspect T, the test sensor of any one ofpreceding aspects R or S further includes that at least one of the firstoptically transparent portions is physically separated from another ofthe first optically transparent portions of the serial calibration codepattern by an optically non-transparent material.

According to an alternative aspect U, the test sensor of any one ofpreceding aspects R to T further includes that the synchronization codepattern has evenly distributed serial openings each separated by evenlydistributed optically non-transparent material.

According to an alternative aspect V, the test sensor of any one ofpreceding aspects R to U further includes that the test sensor includesa reagent, the reagent including glucose oxidase or glucosedehydrogenase.

According to an alternative aspect W, the test sensor of any one ofpreceding aspects R to V further includes that the serial calibrationcode pattern includes between about eight and about sixteen opticallytransparent first openings and the synchronization code pattern includesbetween about eight and about sixteen optically transparent secondopenings.

According to an alternative aspect X, the test sensor of any one ofpreceding aspects R to W further includes that the serial calibrationcode pattern and the synchronization code pattern together occupy lessthan 0.06 square inches of a top surface of the strip.

According to an alternative aspect Y, the test sensor of any one ofpreceding aspects R to X further includes that the serial calibrationcode pattern and the synchronization code pattern together occupy lessthan 0.03 square inches of a top surface of the strip.

According to an alternative aspect Z, a biosensor system for determiningan analyte concentration in a biological fluid includes a measurementdevice including a processing unit connected to an optical pattern readdevice, the optical pattern read device including one or more lightsources, a first light sensor, and a second light sensor; and a sensorstrip including sequential data coding patterns including firstoptically transparent openings and separate correspondingsynchronization coding patterns including second optically transparentopenings, wherein the one or more light sources are configured totransmit light waves through the first and second optically transparentopenings, the one or more light sources being at least partiallypositioned on a first side of the first and second optically transparentopenings, wherein the first light sensor is positioned on an oppositeside of the first optically transparent openings and the second lightsensor is positioned on an opposite side of the second opticallytransparent openings, the first light sensor and the second light sensorconfigured to receive transmitted light waves from the one or more lightsources, wherein the light waves are transmitted by the one or morelight sources and received by the first light sensor and the secondlight sensor while the sensor strip is being inserted into themeasurement device such that light waves received by the second lightsensor associated with the synchronization coding patterns providesynchronization for the light waves received by the first light sensorassociated with the sequential data coding patterns.

According to an alternative aspect AA, the biosensor of the precedingaspect further includes that the sequential data coding patterns and thesynchronization coding patterns cause a series of corresponding positiveand negative code signals to be generated by the optical read headdevice and received by the processing unit while the sensor strip isinserted into the measurement device, the measurement device and sensorstrip being configured to implement an analyte analysis having at leastone correlation equation associated with the sequential data codingpatterns, the processing unit configured to calibrate the at least onecorrelation equation in response to the generated code signals receivedfrom the optical pattern read device, the processing unit furtherconfigured to determine an analyte concentration responsive to the atleast one calibrated correlation equation.

According to an alternative aspect AB, the biosensor of any one ofpreceding aspects Z or AA further includes that the sequential data codepatterns include between eight and sixteen sequential first opticallytransparent openings, and wherein the synchronization coding patternsinclude between eight and sixteen sequential and evenly spaced secondoptically transparent openings.

According to an alternative aspect AC, the biosensor of any one ofpreceding aspects Z to AB further includes that at least a portion ofthe sequential data coding patterns are apertures in the sensor strip.

According to an alternative aspect AD, the biosensor of any one ofpreceding aspects Z to AC further includes that at least a portion ofthe synchronization coding patterns are apertures in the sensor strip.

According to an alternative aspect AE, the biosensor of any one ofpreceding aspects Z to AD further includes that the sequential datacoding patterns are distributed along a length of the sensor strip, thesynchronization coding patterns having the same length as the sequentialdata coding patterns.

According to an alternative aspect AF, the biosensor of any one ofpreceding aspects Z to AE further includes that the sequential datacoding patterns are disposed on the sensor strip parallel to thesynchronization coding patterns.

According to an alternative aspect AG, the biosensor of any one ofpreceding aspects Z to AF further includes that the synchronizationcoding patterns are evenly distributed optically transparent sequentialopenings on a surface of the sensor strip such that each adjacentoptically transparent synchronization opening is separated by anoptically non-transparent material.

According to an alternative aspect AH, the biosensor of any one ofpreceding aspects Z to AG further includes that the sequential datacoding patterns and the synchronization coding patterns are parallel andphysically separated by a portion of the surface of the sensor stripalong the entire length of the respective coding patterns.

According to an alternative aspect AI, the biosensor of any one ofpreceding aspects Z to AH further includes that the sensor strip has afirst edge and an opposing second edge, the sequential data codingpatterns being sequentially positioned along the first edge and thesynchronization coding patterns being sequentially positioned along theopposing second edge.

According to an alternative aspect AJ, the biosensor of any one ofpreceding aspects Z to AI further includes that the sequential datacoding patterns and the synchronization coding patterns include one ormore apertures in the sensor strip, each coding pattern aperture beingrectangular and defined along only three sides by opticallynon-transparent material of the sensor strip.

According to an alternative aspect AK, the biosensor of any one ofpreceding aspects Z to AJ further includes that the biosensor includes areagent, the reagent including glucose oxidase or glucose dehydrogenase.

According to an alternative aspect AL, the biosensor of any one ofpreceding aspects Z to AK further includes that the one or more lightsources includes a single LED light and two light guides for receivinglight from the LED light and redirecting the light waves to the firstoptically transparent openings and the second optically transparentopenings, the light waves being directed by total internal reflectionwithin the two light guides, the two light guides being configured toemit light beams narrower than the smallest dimension of the opticallytransparent openings.

According to an alternative aspect AM, the biosensor of any one ofpreceding aspects Z to AL further includes that the one or more lightsources includes a two LED lights, one LED light being positioned totransmit light waves through the first optically transparent openingsand into the first light sensor, the other LED light being positioned totransmit light waves through the second optically transparent openingsand into the second light sensor.

According to an alternative aspect AN, the biosensor of any one ofpreceding aspects Z to AM further includes that each of the one of morelight sources includes a mask configured such that the one or more lightsources emit a light beam narrower than the smallest dimension of theoptically transparent openings.

According to an alternative aspect AO, the biosensor of any one ofpreceding aspects Z to AN further includes that the light sensorsgenerate a sequence of pulses in response to the light waves beingtransmitted through the first optically transparent openings associatedwith the sequential data coding patterns and the second opticallytransparent openings associated with the synchronization codingpatterns.

According to an alternative aspect AP, the biosensor of any one ofpreceding aspects Z to AO further includes a sensor strip detectionsystem for detecting the sensor strip being inserted into a port of themeasurement device, wherein the sensor strip is detected immediatelyprior to commencing the optical reading of the sequential data codingpatterns and the synchronization coding patterns.

According to an alternative aspect AQ, a method for determining ananalyte concentration in a biological fluid using a calibratedcorrelation equation includes the following acts: (a) transmitting lightwaves through first optically transparent openings in a test sensorincluding a first row of sequential optically transparent andnon-transparent positions forming calibration coding patterns; (b) nearsimultaneous to act (a), transmitting light waves through secondoptically transparent openings in the test sensor including a second rowof sequential optically transparent and non-transparent positionsforming synchronization coding patterns that correspond to thecalibration coding patterns; (c) receiving the light waves transmittedthrough the first optically transparent openings in a first lightsensor; (d) receiving the light waves transmitted through the secondoptically transparent openings in a second light sensor; (e) generatinga series of calibration code signals in response to light waves beingreceived and not received by the first light sensor due to the opticallytransparent and non-transparent positions passing the first light sensorduring the insertion of the test sensor into an analyte measuringdevice; (f) near simultaneous to act (e), generating a series ofsynchronization code signals in response to light waves being receivedand not received by the second light sensor due to the opticallytransparent and non-transparent positions passing the second lightsensor during the insertion of the test sensor into the analytemeasuring device, the series of synchronization code signalscorresponding to the series of calibration code signals; (g) calibratingat least one correlation equation in response to the generating theseries of calibration code signals; and (h) determining an analyteconcentration based on the at least one calibrated correlation equation,wherein the analyte concentration is determined by reacting the analytein a reaction that produces an output signal, the analyte concentrationbeing determined using the at least one calibrated correlation equationand the produced output signal.

According to an alternative aspect AR, the method of the precedingaspect further includes detecting the insertion of the test sensor intoan insertion port of an analyte meter, the detecting occurringimmediately prior to the transmitting of light waves in steps (a) and(b).

According to an alternative aspect AS, the method of any one ofpreceding aspects AQ or AR further includes that the calibration codingpatterns have a length, the synchronization coding patterns having thesame length as the calibration coding patterns.

According to an alternative aspect AT, the method of any one ofpreceding aspects AQ to AS further includes that the second row ofsequential optically transparent and non-transparent positions areevenly spaced.

According to an alternative aspect AU, the method of any one ofpreceding aspects AQ to AT further includes that the calibration codingpatterns are disposed on the test sensor parallel to and physicallyseparated from the synchronization coding patterns by an opticallynon-transparent portion of the strip.

According to an alternative aspect AV, the method of any one ofpreceding aspects AQ to AU further includes that the test sensor is fordetermining blood glucose concentration.

According to an alternative aspect AW, the method of any one ofpreceding aspects AQ to AV further includes that at least a portion ofthe sequential optically transparent and non-transparent positions arelinearly arranged.

According to an alternative aspect AX, the method of any one ofpreceding aspects AQ to AW further includes that at least a portion ofthe sequential optically transparent and non-transparent positions arestaggered.

According to an alternative aspect AY, the method of any one ofpreceding aspects AQ to AX further includes that the reaction is anelectrochemical reaction and the output signal is an electric signal.

Each of these embodiments and obvious variations thereof is contemplatedas falling within the spirit and scope of the claimed invention, whichis set forth in the following claims. Moreover, the present conceptsexpressly include any and all combinations and subcombinations of thepreceding elements and aspects.

The invention claimed is:
 1. A method for determining an analyteconcentration in a biological fluid using a calibrated correlationequation, the method comprising the following acts: (a) transmittinglight waves through first optically transparent openings in a testsensor including a first row of sequential optically transparent andnon-transparent positions forming calibration coding patterns; (b) nearsimultaneous to act (a), transmitting light waves through secondoptically transparent openings in the test sensor including a second rowof sequential optically transparent and non-transparent positionsforming synchronization coding patterns that correspond to thecalibration coding patterns; (c) receiving the light waves transmittedthrough the first optically transparent openings in a first lightsensor; (d) receiving the light waves transmitted through the secondoptically transparent openings in a second light sensor; (e) generatinga series of calibration code signals in response to light waves beingreceived and not received by the first light sensor due to the opticallytransparent and non-transparent positions passing the first light sensorduring the insertion of the test sensor into an analyte measuringdevice; (f) near simultaneous to act (e), generating a series ofsynchronization code signals in response to light waves being receivedand not received by the second light sensor due to the opticallytransparent and non-transparent positions passing the second lightsensor during the insertion of the test sensor into the analytemeasuring device, the series of synchronization code signalscorresponding to the series of calibration code signals; (g) calibratingat least one correlation equation in response to the generating theseries of calibration code signals; and (h) determining an analyteconcentration based on the at least one calibrated correlation equation,wherein the analyte concentration is determined by reacting the analytein a reaction that produces an output signal, the analyte concentrationbeing determined using the at least one calibrated correlation equationand the produced output signal.
 2. The method of claim 1, furthercomprising detecting the insertion of the test sensor into an insertionport of an analyte meter, the detecting occurring immediately prior tothe transmitting of light waves in steps (a) and (b).
 3. The method ofclaim 1, wherein the second row of sequential optically transparent andnon-transparent positions are evenly spaced.
 4. The method of claim 1,wherein the test sensor is for determining blood glucose concentration.5. The method of claim 1, wherein at least a portion of the sequentialoptically transparent and non-transparent positions are staggered. 6.The method of claim 1, wherein the reaction is an electrochemicalreaction and the output signal is an electric signal.